DeWalt 20V MAX vs FLEXVOLT: What's the Difference (and What's Compatible)?
20V MAX is DeWalt's single-voltage system — nominal 18V, marketed as 20V max. FLEXVOLT is a battery that automatically switches voltage: it runs at 20V in a 20V MAX tool and 60V in a FLEXVOLT tool. Here's the one rule that matters: a FLEXVOLT battery runs your 20V MAX tools, but a 20V MAX battery can't run a 60V FLEXVOLT tool. Both share the same battery foot, so a FLEXVOLT pack drops right onto a 20V tool — and your existing 20V chargers and accessories still work. Which one you buy depends on the tools you own.
What is DeWalt 20V MAX?
20V MAX is the everyday cordless line — drills, impact drivers, circular saws, the stuff most people own. It's a single-voltage platform: every 20V MAX battery puts out the same voltage, nominal 18V (the "20V max" name is the peak voltage before you put it under load).
If your toolbox is drills and drivers, this is the platform you're on. One battery type, one charger, simple.
What is DeWalt FLEXVOLT?
FLEXVOLT is the clever one. It's a battery that reconfigures its own cells to deliver two different voltages depending on the tool you snap it into — 20V in a 20V MAX tool, 60V in a FLEXVOLT tool. You don't flip a switch; the tool does it automatically when the battery seats.
The point of FLEXVOLT is high-demand tools: miter saws, grinders, big circular saws — gear that wants 60V to pull real power. The same battery then steps down to run your regular 20V tools.
20V MAX vs FLEXVOLT: the compatibility rules (the part that matters)
This is what people actually want to know. The table:
| Battery | Runs in 20V MAX tools? | Runs in 60V FLEXVOLT tools? | Charges on a 20V MAX charger? |
|---|---|---|---|
| 20V MAX | Yes | No | Yes |
| FLEXVOLT | Yes (at 20V) | Yes (at 60V) | Yes |
Spelled out: a FLEXVOLT battery runs everything — it powers your 20V MAX tools at 20V and your FLEXVOLT tools at 60V. A 20V MAX battery only runs 20V MAX tools. Drop a 20V MAX pack onto a 60V FLEXVOLT miter saw and it won't run it — the tool needs 60V the 20V pack can't supply.
So the cross-over only goes one direction. FLEXVOLT down to 20V: fine. 20V up to 60V: no.
Do they share the same charger and accessories?
Yes — and this is the part that saves you money. Both batteries use the same battery foot, the rail that slides onto your tools. That means:
- Your DeWalt 20V MAX charger charges a FLEXVOLT pack (it charges it in 20V mode).
- Any accessory that fits a 20V MAX battery fits a FLEXVOLT battery too — same foot.
So a DeWalt 20V USB charger or a DeWalt power inverter that snaps onto a 20V MAX pack will snap onto a FLEXVOLT pack the same way. You're not buying separate accessories for each. For more on the charger-side details, see our DeWalt 20V USB charger adapter guide.
Which should you buy?
Match the battery to your tools:
- You only own 20V MAX tools: a plain 20V MAX pack is all you need. FLEXVOLT would just cost more and add weight for capability you can't use.
- You own or plan to buy a 60V FLEXVOLT tool: you need FLEXVOLT. Nothing else runs those tools.
- You want one battery for both, plus longer runtime in your 20V tools: FLEXVOLT. It holds more cells, so it runs 20V tools longer — you just pay more and carry a heavier pack.
If you're cross-shopping batteries, our POWERSTACK vs FLEXVOLT compatibility and POWERSTACK vs 20V MAX guides cover where DeWalt's newer POWERSTACK packs fit in.
FAQ
Will a FLEXVOLT battery work in a 20V MAX tool? Yes. A FLEXVOLT battery runs at 20V in a 20V MAX tool and fits the same battery foot.
Will a 20V MAX battery work in a FLEXVOLT (60V) tool? No. A 60V FLEXVOLT tool needs a FLEXVOLT battery; a 20V MAX pack can't supply 60V.
Can I charge a FLEXVOLT battery on a 20V MAX charger? Yes. FLEXVOLT packs charge on standard DeWalt 20V MAX chargers.
Is FLEXVOLT just a bigger 20V battery? No. It's a battery that reconfigures its cells to deliver either 20V or 60V depending on the tool you put it in.
Do my 20V MAX accessories fit a FLEXVOLT battery? Yes. They share the same battery foot, so USB adapters and inverters that fit a 20V MAX pack fit FLEXVOLT too.
Sorting out which battery fits your setup? Browse the DeWalt collection for the chargers, USB adapters, and inverters that work across both 20V MAX and FLEXVOLT packs.